Air masses of Central Siberia. Features of the nature of Central Siberia
Climate of Western Siberia
Climate Western Siberia- continental, quite severe. It is more severe than the climate of the Russian Plain, but milder than the rest of Siberia. Continentality increases to the south, as you move away from the coast of the Arctic Ocean.
The large meridional extent causes significant differences in the amount of solar radiation between the north and south of the plain. The total radiation varies from 70 to 120 kcal/cm² per year, while the radiation balance varies from 15 to 40 kcal/cm² per year. The West Siberian Plain, in comparison with the Russian Plain, receives more solar radiation at the same latitudes due to an increase in direct solar radiation due to the lower frequency of cyclonic weather accompanied by cloudiness.
Geographical position determines the predominance of the western transfer of air masses, but the considerable remoteness of the plain from the Atlantic Ocean contributes to the weakening of the influence of Atlantic air masses on the formation of its climate.
The flatness of the territory, its openness from the north and south ensure free meridional transport, which smooths out temperature and weather differences.
The nature of the underlying surface also has a significant influence on the most important climatic indicators: large swampiness, lakes and forests of the plain.
During the cold period, the climate of Western Siberia is formed under the influence of the southern part the plains of the spur of the Asian High and the low-pressure trough located above the Kara Sea and the peninsulas, stretching from the Icelandic Low. A gradual drop in pressure from the southern margins of the plain to the northern margins contributes to the removal of cold continental air of temperate latitudes from the Asian High and filling the entire territory with it. Southerly winds prevail. Winter is characterized by a stable negative temperature. Absolute minima reach in the south - 45... - 50°, in the center and in the north - 55°С.
The warmest is the southwest of the plain. In the southern and central parts (up to approximately 65°N) there is a decrease in temperature from southwest to northeast from -17 to -28°C. It is about 10° colder than the Narus plain, but 7–10° warmer than in Central Siberia. Cyclones from the west, northwest, and sometimes from the southwest often come to the northern regions of the plain along the outskirts of the low-pressure trough. They are associated with heat advection from the North Atlantic and Barents Sea. Therefore, in the northern part of Western Siberia, January temperatures change from west to east, from -22°С in the foothills of the Urals to -29°С in the lower reaches of the Yenisei.
Active cyclonic activity along the Arctic front line and the penetration of polar front cyclones from the southwest disrupt the stability of anticyclone weather and create large baric gradients. As a result, strong winds arise with snowstorms and snowstorms (blizzards), especially in the north (up to 35 - 40 m/s) and in the southern sparsely forested and treeless Regions (up to 15 - 20 m/s).
The cold period accounts for 20% in the southern regions, and 35% of the annual precipitation in the northern regions. From November to March, the entire territory of Western Siberia is covered with snow. In the north, snow cover is established already in mid-October and remains for 250 - 270 days a year. To the south, the duration of snow cover is reduced to 150 - 160 days. In the forest zone, the thickness of the snow cover exceeds 50 - 60 cm, reaching a maximum in the eastern part of the zone. In the tundra it decreases to 40-50 cm, and in the steppe zone - up to 25-30 cm. Transitional seasons in Western Siberia are short (1-1.5 months).
AT warm period over the central regions of the Arctic Ocean remains high blood pressure. Over Western Siberia, the pressure gradually decreases to the southeast. This is due to the predominance of winds with a northern component. The role of western transport is also increasing, as a vast Asian depression is being formed over the mainland. However, the baric gradient is small, so wind speeds decrease compared to winter.
Cold dry Arctic air, entering the land surface, warms up quickly, so the temperature gradient in the northern part of the plain is high. The average temperature in July on the northern coast of Yamal is + 4 °C, and near the Arctic Circle + 14 °C. To the south, the rise in temperature is slower. In the far south average temperature July is + 21 - 22 °С. The absolute maximum in the north is +23 - 28°С, and in the south +45°С.
The warm period (from April to October) in Western Siberia accounts for 70-80% of the annual precipitation. They are most abundant in July and August, which is associated with cyclogenesis on the Arctic and Polar fronts. In the tundra, the maximum precipitation occurs in August, in the taiga - in July, and in the steppes - in June.
In the warm period in the southern regions of Western Siberia, months are possible in some years when there is no precipitation at all. Summer precipitation often has a shower character, but their daily amount rarely exceeds 10 mm.
The distribution of precipitation over the territory has a zonal character. The greatest number of them (550 - 650 mm) falls in the strip stretching from the Urals to the Yenisei through the middle reaches of the Ob (forest zone). Within this band, there is a slight increase in precipitation to the east, due to the barrier role of the Central Siberian Plateau and an increase in air humidity when passing over the marshy surface of the plain.
North and south of the strip highest rainfall their number gradually decreases to 350 mm. To the north, this is due to an increase in the frequency of arctic air with low moisture content, and to the south, due to a weakening of cyclonic activity and an increase in temperatures.
The plain, especially its southern part, is characterized by significant fluctuations in the amount of precipitation from year to year. In the forest-steppe and steppe zones, precipitation in a wet year can exceed the sum of precipitation in a dry year by 3–3.5 times, in the southern part of the taiga 2–2.5 times.
The climate in most of the territory of Western Siberia contributes to the widespread development of permafrost, in the distribution of which zonality is clearly traced.
Permafrost is found everywhere on the peninsulas. Its thickness is 300 - 600 m. To the south, approximately to the Siberian Ridges, permafrost with talik islands is distributed. The monolithic permafrost here is replaced by a two-layer one: the upper layer of modern permafrost with a thickness of 50 - 100 m in the north to 10 - 50 m in the south is separated by a layer of thawed rocks from the lower, relict layer, starting at a depth of 80 - 140 m and having a thickness of up to 200 - 250 m. m.
Separate islands of modern permafrost are found up to the latitude of the mouth of the Demyanka River (the right tributary of the Irtysh) - Somewhat to the south (up to the sublatitudinal segment of the Irtysh), relict permafrost is widespread (it is absent only on the floodplains of large rivers), occurring at a depth of 100 - 120 to 250 m and having a thickness from 150 to 250 m. In the direction from west to east, an increase in thickness and a decrease in the temperature of frozen soils are observed.
moisture circulation
Among the geographical problems of Western Siberia, an important place is occupied by the study of its moisture management, elucidation of its influence on natural features and conditions for the development of the territory, as well as consideration of possible ways of its transformation. The study of the water balance of Western Siberia or its individual parts helps to assess different sources water resources, allows you to identify possible ways to optimize moisture circulation.
To study the moisture cycle in the territory of Western Siberia, it is necessary to trace the spatial change in the components of the water balance: precipitation (as already mentioned above) and evaporation. Evaporation capacity increases following an increase in temperature from 150 mm near the northern borders of the plain to 650-700 mm in the steppe zone.
At the southern border of the forest zone, the amount of precipitation and evapotranspiration are almost equal to each other (about 500 mm), here the evaporation is greatest (350 - 400 mm), and the moisture coefficient is equal to one.
"(In addition to the moisture coefficient, this ratio in climatology is characterized by the difference in precipitation and evaporation. In the northern part of the plain it is positive (up to 200-250 mm), and in the southern part it is negative (up to 300-350 mm))
To the north and south of this boundary, the structure of the water balance is heterogeneous.
Northern and central parts Western Siberia (more than 80% of its area) has a moisture coefficient greater than 1. These are waterlogged and extremely humid territories. Evaporation here is limited solely by the amount of evaporation. A study of the water balance of this territory, carried out by employees of the Institute of Geography of the Academy of Sciences of the USSR, showed that only due to precipitation here annually, on average, a layer of moisture from 5 to 10 mm is retained and accumulated (Vendrov et al., 1966). It is used to replenish groundwater and lakes, to moisten the soil, but it is mainly preserved in the thickness of continuously growing peat tracts. To retain this moisture, the annual growth of peat should be between 0.5 and 1.0 cm over the entire area. In fact, much more water accumulates here every year, since part of the moisture brought from the surrounding territories by river runoff is also conserved. The northern and central parts of the plain are among the most waterlogged spaces on the entire surface of the Earth. This stimulates the continuous growth of swamps, an increase in the thickness of the peat and the expansion of the swamp area. Many areas are practically inaccessible to land and water transport, which makes it difficult for the economic development of the territory.
The study of the structure of the water balance showed that the main reason for waterlogging lies in the low amount of runoff in relation to precipitation, in the insufficient level of training of the plain.
In the forest-bog zone of Western Siberia, the runoff varies from 100 to 300 mm, which corresponds to a runoff coefficient of 0.2–0.4. At the same latitudes of the Russian Plain, it is 1.5 - 2.0 times greater. Thus. waterlogging, slow moisture circulation in Western Siberia are associated primarily with its lithogenic basis.
The flat relief and the presence of numerous depressions in the interfluve spaces, contributing to the stagnation of water, weak infiltration of atmospheric precipitation due to the alternation of sandy-clay deposits, small surface slopes, the fall and longitudinal slopes of rivers, a weak incision of river valleys, rare river flow - all this complicates the processes of runoff , significantly reduces river runoff in comparison with other regions and slows down the moisture cycle.
To combat waterlogging, it is necessary to increase surface runoff. This can be achieved by straightening the channels of the rivers and thereby increasing the descent. The carrying capacity on the straightened sections of the rivers increases by l.5 - 2.0 times, which makes it possible to drain large land masses. Forests and peat resources will become more accessible, it will be easier to develop the subsoil. The accelerated flow will wash the riverbeds, ensure their better self-cleaning, prevent fish kills, and improve the conditions for their feeding and spawning. Small water intakes in the upper parts of the Ob, Irtysh and their tributaries, the laying of canals and field water pipelines will make it possible to partially compensate for the lack of moisture in the southern regions and reduce its inflow into the central part of the plain.
The southern part of Western Siberia belongs to the region of insufficient and unstable moisture; the moisture coefficient here is less than 1. Evaporation is limited by the amount of precipitation and decreases towards the south. In the same direction, the moisture deficit is growing due to a decrease in precipitation and a simultaneous rapid increase in evaporation. From 85 to 98% of the annual precipitation is spent on evaporation; the runoff layer in the forest-steppe does not exceed 10 - 15 mm, and in the extreme south - 5 - 10 mm. The runoff coefficient decreases to the south from 0.1 to 0.02. The rivers that start here are shallow. Transit rivers almost do not receive tributaries. Many rivers are fed by snow waters. In the spring, high and short floods form on them, but already in the middle of summer the rivers dry up.
Surface runoff in areas of insufficient and unstable moisture leads to moisture loss, and therefore is an unfavorable element of the water balance. The surface remains without moisture for most of the growing season, since summer precipitation evaporates very quickly and almost does not enter the soil.
In years when rainfall is less than normal, droughts occur in the southern part of the country, reducing crops. Droughts recur on average every 3-4 years and occur most often in May-June. As in the Russian Plain, they are usually associated with the intrusion of Arctic air. Sometimes the cause of drought is the entry of very warm and dry air masses from Central Asia and Kazakhstan. Strong winds cause dust storms in summer. The number of days with dust storms is 10 - 15. In dry years, it doubles. The occurrence of dust storms is facilitated by the presence of light sandy and light loamy soils, carbonate soils plowed without special anti-deflation measures, low forest cover in the north and treelessness in the south.
Limitation water resources requires additional moistening of agricultural land, forces one to resort to measures to accumulate and save moisture (snow retention, creation of wings, etc.), in some places and to irrigate land masses
Water
Western Siberia is characterized huge crowd superficial and groundwater, enclosed in many thousands of large and small lakes, vast swamps, slowly flowing full-flowing rivers, abundant groundwater and large artesian basins.Rivers. The surface of the plain is drained by many thousands of rivers, the total length of which exceeds 250,000 km. Most of rivers belongs to the basin of the Kara Sea. Almost the entire plain is included in the Ob basin. Only the rivers of the northern part of the plain carry their waters directly to the Kara Sea or its bays (Taz, Pur and Nadym). Some areas of the Kulunda, Baraba and Ishim plains belong to the area of internal (closed) runoff. The rivers here flow into drainless lakes, and in dry years they dry up completely. The density of the river network in different parts the plains are not the same. It reaches its greatest value in the Ural part of the forest-bog zone (0.35 - 0.30).
Due to the scarcity of the territory and the slight slope of the surface of the rivers of Western Siberia, including the largest Ob, Irtysh, Yenisei, they are distinguished by small longitudinal slopes, slow smooth flow and the predominance of lateral erosion. The longitudinal slopes of the Ob in the middle and lower reaches are only 1.5 - 3.0 cm/km. This is 3 - 4 times less than the slopes of the Northern Dvina and 10 - 12 times less than that of the Amu Darya. The slope of the Yenisei is 1.5 - 2 times greater than that of the Ob. With a small fall, the rivers strongly meander, wandering along a wide floodplain, reaching a width of 15–20 km on large rivers, forming numerous branches, channels and meanders. The sinuosity factor of many rivers is 2.5 - 3 .
The rivers are fed by melted snow, rain and marsh groundwater. Snow feeding comes first in all rivers. Its share is growing in the direction from north to south. Snow melting is associated with spring floods on the rivers, the peak of which in the northern part shifts to the beginning of summer. The peak of the flood on the Ob reaches 7-12 m, and in the lower reaches of the Yenisei even 18 m
The West Siberian rivers are characterized by excessively spread (protracted) floods. Only the rivers of the southern regions are distinguished by rapid short-term floods and a rapid decline in water. In the rest of the territory, the flood extends for 2-3 summer months. The rise of the water is very fast, and high level lasts a long time and falls off very slowly. This is due to the features of the relief that slow down the runoff, as well as the fact that the main water arteries of Western Siberia, the Ob, Irtysh and Yenisei, flow from the south, where the flood begins earlier. As a result, these high-water rivers cause backwaters on the tributaries of their middle and lower reaches. The prolonged spring-summer flood greatly weakens the draining role of rivers and even transforms them from a drainage factor into a factor of stagnation and temporary accumulation of water.
Freezing on the rivers of the southern part of Western Siberia lasts 5 months a year, and on the northern ones - up to 7 - 8 months. During the period of spring ice drift, powerful ice jams occur on large rivers, since the opening begins in the upper reaches, gradually spreading to the north. The duration of the ice drift in the lower reaches of the Ob and Yenisei is about a month.
major rivers Western Siberia are navigable. The Yenisei, the Ob and the Irtysh are navigable along almost their entire length within the plain. In the lower reaches of the Yenisei (to Dudinka) and sea vessels, as the depths here reach 50 m.
Ob is one of the greatest rivers the world is the main river of the plain. The area of its basin is about 3 million km², the length from the sources of the Irtysh is 5410 km. If we consider the length of the Ob from the source of the Katun, then it reaches 4345 km, and from the confluence of the Biya and Katun - 3676 km. The annual flow of the Ob is about 400 km³, and the average annual discharge is 12,400 m³/s. In terms of water content, the Ob occupies the third place in Russia, second only to the Yenisei and the Lena. The river flows into the Gulf of Ob, which is a typical estuary. The underwater valley can be traced further, at the exit from the Gulf of Ob, in the adjacent part of the sea.
On the left, the Ob takes its largest tributary Irtysh, whose basin occupies half of the Ob basin, and the length from the sources of the Black Irtysh reaches 4248 km. The flow of the Irtysh is one third of the flow of the Ob. The tributaries of the Irtysh - Ishim, Tobol and Konda, as well as the tributaries of the Ob - Chulym, Ket and Vasyugan have a length of more than 1000 km. The Ob and Irtysh with their tributaries within Western Siberia are typical lowland rivers with low slopes and a calm course.
The area of the Yenisei basin is a little over 2.5 million km². On the territory of Western Siberia, there is only a small left-bank part of the basin, along which short, slightly watery tributaries flow. The Yenisei begins in the mountains of Tuva and flows into the Yenisei Gulf of the Kara Sea. In the upper reaches, it is a stormy mountain river with a large longitudinal slope. In the middle reaches, where the river is pressed against the ledge of the Central Siberian Plateau, there are large rapids in its channel, and the current has a high speed. Only in the lower reaches of the Yenisei does the river acquire a calm current. The length of the river is 4092 km, the annual flow is about 625 km³, and the average annual flow is 19800 m³ / s. This is the most abundant river in the country.
Lakes. On the West Siberian Plain there are about 1 million lakes with a total area of more than 100 thousand km². The lake content varies from 1 - 1.5% - in the south to 2 - 3% - in the north. In a number of areas it reaches 15 - 20% (Surgut lowland). A large number of lakes is due to the flatness and poor fitness of the territory. The lakes are located both on watershed plains and in river valleys. The water of many lakes in the southern part of the plain is salty and brackish. The largest lake in Western Siberia is Lake Chany. This is a shallow shallow reservoir. At the beginning of the last century, the area of its mirror was more than 8 thousand km², and at present it is about 2 thousand km². Max Depth- less than 10m.
The groundwater. In terms of hydrogeological conditions, the plain is a huge West Siberian artesian basin, which consists of a number of second-order basins: the Ob, Tobolsk, Irtysh, Chulym, Baraba-Kulunda, and others. The waters lie at different depths in the Meso-Cenozoic deposits. In the marginal parts of the plain, underground waters were discovered, concentrated in cracks in the dense basement rocks. The presence of numerous aquifers is associated with the large thickness of the cover of loose deposits, consisting of alternating permeable and impervious rocks. They differ in different chemistry, regime and water quality. The waters of deep horizons are usually more mineralized than those closer to the surface. In the southern regions, the waters of the upper horizons are often strongly saline. This is due to high evaporation, poor surface fitness and slow water circulation. In some aquifers at depths from 800 to 3000 m, waters with a temperature of 25-120 °C are revealed. Usually these are highly mineralized waters that can be used for heating and medicinal purposes. General stocks groundwater in Western Siberia is about 13% of the total.
Swamps. The swamps of Western Siberia are a colossal reservoir of water. The average swampiness of the plain is about 30%, in the peat-bog zone it is about 50%, and in some areas (Surgut Polissya, Vasyuganye, Kondinskaya lowland) it reaches 70-80%. The largest in the world is the Vasyugan swamp with a total area of 53,000 km2. A combination of many factors contributes to the widespread development of swamp formation, the main of which are the flatness of the territory and its tectonic regime with a steady tendency to subside in the northern and central regions, poor drainage of the territory, excessive moisture, prolonged spring-summer floods on the rivers in combination with the formation of backwater for tributaries and an increase in the level of the Ob, Irtysh and Yenisei, the presence of permafrost.
According to the data of the peat fund, the total area of peat bogs in Western Siberia is 400 thousand km², and with all other types of bogging - from 780 thousand to 1 million km². The total peat reserves are estimated at 90 billion tons in the air-dry state. It is known that bog peat contains 94% water. Consequently, the entire mass of peat in Western Siberia contains at least 1000 km³ of water. This is equal to the 2.5-year runoff of the Ob.
The characterization of the Siberian climate is hampered by its extreme diversity in various parts region, however, the data meteorological observations make it possible to recognize the climate of Siberia as quite severe.
At the same time, the long duration and low temperature of winter is compensated by a rapidly developing spring and a relatively hot summer; the average daily temperature in late March and early April rises in Verkhoyansk faster than anywhere else in the world, namely more than half a degree per day, and July there corresponds to the average annual temperature of the 50th parallel. During the short summer in Yakutsk, many vegetables ripen, and the barley sown in May is already harvested in mid-July. Rye and even wheat are sown in Yakutsk, and this is despite the presence of permafrost only at a depth of 1 meter. And the frosts themselves in Siberia, thanks to the usual calmness, are easier to bear than in other places. If we add to this that the average winter cloudiness in Siberia is about 50% and that it is especially small in the Lena basin, due to which (and the negligible amount of water vapor in the atmosphere) even a low rising sun warms so that sometimes even at -25 ° it drips from the roofs, then the widespread opinion about the severity should be considered exaggerated.
Cloudy December day. Calm.
As an unfavorable feature of the climate of Siberia for man and economy, it should be noted its inconstancy both from day to day and in different years. So, for example, variability average daily temperature from day to day is 3.6° in January and 1.7° in July for Irkutsk, 4.5° and 2.0° for Yakutsk, and 4.0° and 3.3° for Verkhoyansk, while for most year in the European part of Russia it is less than 2°. The number of days in a month when the change per day is more than 6° is 1.0 in winter and 0.3 in summer for Western Europe, while for Western Siberia the corresponding figures are 9.0 and 1.7. In some cases, however, these changes in Siberia reach a significant value. So on February 14, 1894 in Yeniseisk from 7 am to 9 pm the temperature rose from -40.3° to -17.0°, and on January 27, 1877 it fell from -12.8° (at 1 pm) to - 42.4° by 7 a.m. the next day. The temperature in Siberia also undergoes significant changes from year to year. All these circumstances, in connection with the possibility of both very late spring and very early autumn frosts, make it difficult for agriculture and especially gardening in many places in Siberia, despite the sufficiency of the amount of heat received during the summer.
General characteristics of the climate of Siberia
To understand the climate of Siberia as a whole, it is necessary to have general idea about the geophysical phenomena by which it is determined. If the surface of the globe were all water or all land, but of the same properties, then at all longitudes of each parallel circle there would be the same climate, depending only on latitude. The presence of both water and land, moreover, land, which differs both in the nature of the surface and its height above sea level, causes differences in climate at different longitudes, determined mainly by the greater heat capacity of water, which heats up more slowly than land, as during daylight hours, and during the transition from winter to summer and cooling more slowly during the night and during the transition from summer to winter. As a result, from the beginning of autumn, the air density over land begins to become greater than over water, as a result of which in the upper layers of the atmosphere an influx of additional air masses towards land is obtained, which, increasing pressure above it, cause in the lower layers the movement of air from the center of the formed in this way the anticyclone to its periphery. The masses of air leaving in these directions are replaced by masses of cold air descending in the central parts of the anticyclone, containing little water vapor, and thereby contribute to a decrease in cloudiness and an even faster cooling of the surface of the central parts of the land. For the same reasons, during the summer a reduced pressure should be established over the land with an influx of moist and warm air from the surrounding seas to the central parts of the mainland in the lower layers of the atmosphere (hence the increase in cloudiness and precipitation atmosphere).
End of September in Western Siberia. October pre-winter is ahead.
The larger the mainland and the closer some area is to its center, the more clearly the continental climate manifests itself, which is expressed in cold, dry and cloudless winters and relatively warm and more abundant precipitation in summer. In coastal areas, a maritime climate is manifested with much milder winters and less warm summer and relatively abundant autumn and winter precipitation. An anticyclone that sets up every winter in Siberia with central part over Northern Mongolia cannot, however, be symmetrical either in the latitudinal or in the longitudinal direction. To the north of it is the Arctic Ocean, much colder than to the south and separated by the Himalayas. Indian Ocean. From the east are the relatively warm Sea of Okhotsk and the Pacific Ocean. The Asian anticyclone is separated from the distant Atlantic Ocean by the Ural Range. Due to these reasons, as well as from the presence of the Stanovoy Range directed to the northeast, a relatively slow spreading of cold air is obtained in a significant part Northern Siberia east. At the end of the Stanovoy Ridge, this eastward-rushing air turns south, as if pouring over the ridge and giving almost continuous strong, dry and cold northern and northeastern winds to the northern coast of the Sea of Okhotsk. Such air circulation is facilitated by the deep “Aleutian” pressure minimum, which forms in winter in the northern part of the Pacific Ocean. On the contrary, in the north-west of Siberia, where the influence of the relatively late freezing Kara Sea and even the distant Gulf Stream is felt, strong southerly winds dominate in winter (in particular, along the lower reaches of the Yenisei), also cold, but not so dry. The farther west from the Yenisei valley, the weaker the northwestern spur of the region high pressure and the less often and shorter are the manifestations of the tongues of the Yakut anticyclone approaching from time to time, bringing a cloudless sky, almost complete calm, severe frosts. But, when one of the winter cyclones that originated in the north of the Atlantic Ocean along a wide low-pressure trough, stretching from there along the northern coasts of Eurasia, or through Northern Ural, or penetrates into Siberia through the Kara Sea, then clear frosty weather is replaced by less cold weather with cloudy skies, snowfall and sharp western winds. Aerological observations in Siberia clearly indicate the existence of an inversion in winter in the region of the Siberian anticyclone (an increase in temperature as it rises above the earth's surface instead of the usual decrease). In the middle parts of Siberia, the lower layers of air, which are strongly cooled on long and clear nights, cannot mix with the upper ones and only drain from more elevated places to valleys, hollows and hollows, where almost all the meteorological stations of Yakutia are located, the observations of which give such low temperatures in winter. The latter serve as an indication that the winter inversion there is not a temporary, but a permanent phenomenon. The Siberian anticyclone begins already in September, reaches its maximum development in February, and then, under the influence of a gradually increasing preponderance of the heating of soil and air by the sun's rays over nighttime cooling, gradually resolves, and in May begins to be replaced by an area of slightly reduced pressure (4-6 mm in compared with the northern and eastern outskirts of Siberia, while the winter increase is about 15-20 mm). In the summer months, high pressure areas are located in the southern steppe zone of the European part of Russia, over the Arctic Ocean and in the subtropical Pacific Ocean. Therefore, the summer weather in Siberia, although it has, in general, a typically continental character, is still very often subject to changes caused both by high pressure areas invading from the southwest and by cyclones penetrating the territory of Western Siberia, mainly from the west (usually bypassing the Urals from the north or south), and in Eastern Siberia mainly from the east, and in Primorye (especially in its southern part) the influence of the Pacific monsoons is distinct.
This general characteristic undergoes noticeable changes in many parts of Siberia due to local orographic features and can therefore only be of general guiding importance for understanding the climate of Siberia, especially the climate of western Siberia, which is one vast plain.
Climate and agriculture of Siberia
The main feature of the climatic conditions of Siberia, which has importance in agriculture region, is their extreme volatility and diversity. On the one hand, we find here all types of farms - from the reindeer farms of the northern tundra to the sugar beet and tobacco plantations of the south, on the other hand, at a comparatively small distance, the same culture develops perfectly in one place, and in another it is almost not applicable at all. .
More tangible for agriculture is the variability of climatic elements, in particular temperature and precipitation over time. The presence of an exceptional difference between the temperature of winter and summer and the stability of winter cold cause a rapid transition from winter to summer temperatures and significantly shorten warm time of the year. At the same time, the short spring and autumn are often significantly lengthened due to the summer, which is quite common for Siberia in the return of severe cold in the spring and the early onset of frost in the fall. Due to this, the absolutely frost-free period is not very long here; and in some years even the most warm month- July.
Due to the low wind speed in the winter months, severe frosts in Siberia are more easily tolerated by animals.
The temperature period of + 5 °, which allows the vegetation of plants, is distinguished, in addition to brevity, by a very noticeable instability from year to year, which is especially felt in the northern regions of Siberia, where summer is the shortest. In particular, in Yakutia, where the vegetation period on average ranges from 130 to 60; in 10 years there are only 2 good crops, 3 medium and 5 bad ones. The duration of the growing season in Siberia increases towards the south and west. So, in the Amur region, this duration already varies from 130 days (54 ° N) to 170 (48 ° N). The norm adopted for the growing season can be considered sufficient, mainly for unpretentious plants, while for most crops the temperature limit should be increased to + 10 °. But even the onset of an average daily air temperature of 10°C does not guarantee the absence of sharp cold spells that are detrimental to agricultural plants. These circumstances not only exclude the possibility of breeding crops that require a longer growing season, but even the crops cultivated here are always under the threat of either underripening or death from frost at the beginning or end of summer.
But if we formally approach the definition of the possibility of growing agricultural crops here, using the climatic signs of their classification established elsewhere, then we can come to the paradoxical conclusion that it is impossible to cultivate a number of even those crops that actually play a significant role in agriculture. Siberia. This contradiction is explained by the fact that in most cases this classification is based on only two climatic signs- air temperature and precipitation - and do not take into account other signs, among such signs there is a factor of tremendous importance - solar energy directly perceived by the plant; it was found that the abundance of light and the influx of solar energy significantly reduce the growing season. And in this regard, Siberia has a certain advantage over other countries located at the same latitudes, which partially compensates for the negative temperature conditions.
No less important in economic terms for Siberia is the instability of precipitation over time. While in the European part of Russia the average long-term deviations of the annual precipitation amounts are 12-18% and only in the south rise to 25% (Astrakhan), in Siberia the average deviation reaches 36%, reaching even 160% in exceptional years. Even greater variability from year to year differs in the amount of precipitation of individual months. For them, the average deviation in Siberia ranges from 21 to 81%. But it should be noted that these deviations are generally greater for the season with less precipitation, i.e. in Siberia they are more for winter months and less for summer, deciding the fate of the crop. However, relatively smaller fluctuations in the amount of precipitation in the summer months are still absolute value are quite large. During the year, with a total, relatively small, annual amount, precipitation in Siberia is still distributed favorably. They fall mainly in the summer in the form of short-term showers, often accompanied by rainfall, with the most abundant precipitation in July and then August. The amount of summer precipitation is from 45 to 70% of the annual amount, and July from 15 to 35%. Also, a greater percentage of precipitation occurs in autumn than in spring. This circumstance, although it is associated with a negative effect on harvesting, must nevertheless be considered favorable for Siberian agriculture. With a strong freezing of the soil and a rapid melting of the snow cover, the main supply of soil moisture in the spring is provided by last year's autumn precipitation. In the same way, the soil moistened since autumn is warmed up more easily and faster by the spring rays of the sun, which in turn helps to accelerate the start of the growing season. However, a comparison of the amount of precipitation and harvests gives grounds to believe that the rainfall at the end of June and, to a lesser extent, at the beginning of July, is of decisive importance in Siberia.
Almost everywhere in the 3rd decade of June and 1st July, on average, a slight decrease in precipitation is observed. This gives grounds to assume a slightly higher probability of aridity in these decades compared to the rest. In general, the frequency in June is less than in spring months and almost equal in comparison with July and August and even with September. It should be noted that, with a relatively lower probability of the onset of dry periods in June, they are not much inferior to the next months in terms of stability: the duration of these periods, in general, differs little from the duration of the periods of other months.
Summer is everywhere more periods of bad weather, with a predominantly longer duration than spring, and a predominantly greater number of such periods than autumn, but the duration autumn periods turns out to be larger in the western part of Siberia and smaller to the east of Baikal. Finally, bad weather in autumn is more frequent and longer than in spring. From this we have to conclude that the weather in Siberia is more favorable for spring field work than for autumn, i.e. good harvest in the vine is still under the threat of unfavorable harvesting conditions.
Precipitation during the winter period, generally very small in Siberia, is insufficient for the formation of a thick snow cover, which is so insignificant here that the Altai, Sayan, Baikal regions and almost the entire east belong to the region of "climates with snowless winters." Due to the weakness of the snow cover, the so-called so-called is widespread in the eastern part of Siberia, and the soil freezes to a considerable depth in the western part. However, permafrost is not an enemy of agriculture: spring crops, including wheat, grow well in these places, since soil water collects above the permafrost, and plants do not suffer from droughts. The strong freezing of the poorly protected soil prevents the spread of winter crops. In general, in Siberia, snow, which usually forms at low temperatures, is extremely fine and dry, and therefore very mobile and easily blown away and carried away by the wind from open fields. In taiga places more protected from the action of the wind, the snow cover is more developed. Therefore, the issue of snow retention measures is of great importance in Siberia.
Speaking about the northern limit of the spread of agriculture in Siberia, one must agree with the thought of A. I. Voeikov that it "can go far to the north, and if it is not there, then it depends only on the small population of the region and the lack of good communications." Indeed, a sufficient amount of precipitation, a very warm summer for the latitudes of Siberia, and an abundance of sunshine are conditions favorable for the development of agriculture. If we turn to the map of "actual and climatically possible northern and upper (mountain) boundaries of agricultural crops in the USSR", compiled by G. Selyaninov, then one can find full confirmation of Voeikov's opinion in it. The map shows "accidental", according to Selyaninov's terminology, crops along the Ob up to Obdorsk, along the Yenisei - to the confluence of the Lower Tunguska, i.e. near the Arctic Circle itself, and then near Verkhoyansk and Srednekolymsk, i.e. far beyond the Arctic Circle. But more than that: Selyaninov, noting also the “accidental” crops near Verkhnekolymsk, which lies south of the Arctic Circle, characterizes the area along the Kolyma River near the Arctic Circle itself as an area of “actual agriculture”, although he refrains from drawing a possible border of agriculture here. Attention is also drawn to the circumstance that in all places where water arteries intersect, the boundary of actual agriculture makes a sharp bend, stretching out to the side along each river for a considerable distance. This clearly confirms the idea that the boundaries of the area of real agriculture in Siberia are currently compressed not by the climatic conditions of the region, but by the vast spaces that have not yet been fully developed.
As for the northern border of the distribution of wheat, a crop more demanding in terms of climatic conditions, this border, despite all the complexity and whimsicalness of its meanders, is still in in general terms reflects the climatic features of the region. Starting at Tobolsk, it gradually descends between Lake Chany and the Ob almost to the latitude of the city of Kamen, then rises again along the Yenisei, above the mouth of the Angara, and then heads southeast to Baikal, crossing the latter already at the latitude of Ulan-Ude. Here, on the one hand, the bend of the isotherms characteristic of this region, which, as a rule, descends to the south between the Irtysh and the Ob and rises to the north along the Yenisei, affects, on the other hand, the microconditions of Eastern Siberia, where there are almost no plains, and in the mountains agriculture is generally hindered and steep slopes and low, due to high altitude, summer temperature. However, south of 53° northern latitude in the mountains of Transbaikalia, as well as in the Sayan Mountains, as well as in the foothills and mountain valleys, there are very favorable conditions for vegetation, despite the short summer: bright sun, sufficient rain, moderately humid air. There are especially many such places in Altai. The indicated coincidence of the characteristic bends of the line of wheat distribution to the north and the isotherms gives reason to think that in this case we have here a significant approximation to the really limiting climatic boundaries. This is also not contradicted by the fact that in Yakutia, in separate islands, wheat has spread even to the latitudes of Yakutsk; significantly smaller temperature fluctuations in the region of the middle reaches of the Lena and its tributaries, the Olekma and Aldan, make the climatic conditions of the region more favorable for agriculture than anywhere else in the same latitudes in Western Siberia. However, the presence of islands along the extreme upper reaches of the Lena, as well as along the Angara and its tributaries, and, in particular, the excessive sinuosity of the line between the Yenisei and the Ob, indicate that all the spaces really accessible to it are far from being covered by wheat.
Siberia is a huge territory located to the east of Ural mountains and extending all the way to the Pacific Ocean. Siberian expanses occupy large area Russian Federation. Of course, such a vast region has a great natural and climatic diversity, because in the north lies the Arctic, and in the south - hot Asian steppes and deserts. However, Siberia has some common features climate, which will be described.
Siberia is one of the coldest regions of the globe. This is due to the remoteness from the seas and the fact that from the west and south the territory is surrounded by mountain ranges that do not allow warm air to pass through. Only in the western and southern regions annual temperature positive, in the rest of the territory it is below zero. The climate is continental and sharply continental with significant (sometimes extremely high) differences in annual and daily temperatures. Winters in Siberia are long and frosty, summers are hot and dry, transitional seasons - autumn and spring - are short and poorly expressed.
Climate of Siberia (Novosibirsk) by months:
Spring
Spring is short throughout almost the entire territory of Siberia, and swift in the north. In March, snow is everywhere, the climatic spring, even in areas with a relatively mild climate, begins only after March 20, and the snow cover disappears after mid-April. In the northern regions, where permafrost, spring comes only in June.
There are many clear days, but the weather is unstable, with sharp cold snaps and even frosts. There is not much rainfall, although there may be short showers.
Summer
Depending on the region, the Siberian summer is very different. In the southern regions it is hot and dry, in the north it is short and cool, although in Yakutia, for example, it is very warm and even hot.
Humidity throughout Siberia is much lower than in other regions of Russia, there is less rain and fog. Most of the precipitation occurs in July and August.
Average daily temperatures are around 20-25 degrees, often rising to 30 degrees and above.
The continental nature of the climate is reflected in the fact that night frosts last longer (until mid-June) and return earlier (already in August).
In Western Siberia, the climatic summer ends according to the calendar, that is, in last days August, and in the tundra and in the east even earlier.
Autumn
The transition from summer to winter occurs much faster in Siberia than in the European part of Russia. In September, the air cools quickly, the atmospheric pressure rises sharply. Even in eastern regions snowfalls can begin at the end of September, and in mid-October the snow cover is already established. In areas with a more severe climate, this happens earlier.
But in September, the weather is still pleasing: there are many sunny days, the temperature can rise to 20 degrees and above. It gets cold quickly, rains are replaced by mixed precipitation, and then snowfalls. Winter comes to Siberia already in the first decade of November.
Winter
Siberian winter is a real test for man and nature. But there are also advantages here: due to the low humidity of the air, frosts are more easily tolerated, a lot sunny days, blizzards and heavy snowfalls are not as annoying as in the European part.
The greatest frosts occur in January. In the eastern regions with the mildest climate average monthly temperatures January are minus 18 degrees, but in Yakutsk this figure is minus 40 degrees, and this is not the limit for the north of Siberia.
The thickness of the snow in Siberia is generally small. Even in the snowiest areas, it does not exceed 70 cm, there are areas where there is almost no snow, but it is very frosty.
For many of our compatriots, and even more so for most foreigners, the concept of Siberia is associated with a very harsh climate. Like many other clichés, this statement is only partly true. Of course, the weather conditions of the Siberian lands do not indulge their inhabitants, but they are not as extreme as it is commonly believed. In addition, the climate tends to change, and Siberia is far from being as harsh as it was 100 years ago.
It is worth paying attention to the fact that Siberia occupies vast territories. There are still disputes about the geographical boundaries of the entire region (you can read more about this here - Geography and borders of Siberia), so when characterizing the climatic conditions of this region, we will limit ourselves only to the boundaries of the Siberian Federal District, conditionally dividing it into the Western, Eastern and Northern parts .
Characteristics of the climate of Western Siberia
We attributed the following regions to the western part of Siberia - Omsk, Tomsk, Novosibirsk and Kemerovo Regions, Altai region and the Republic of Khakassia and Altai. Perhaps this part of Siberia has the mildest climate. Altai mountains cover the above regions from the Kazakh winds, and the extensive Vasyugan swamps soften the summer heat characteristic of continental climate. Average temperature in winter period fluctuates in the range from -15°С to -30°С. Because of strong winds, the frost in these places is felt a little stronger. The snow cover is usually established at the end of November and reaches a thickness of 15-20 cm. The summer period is characterized by a range from +15°С to +35°С, which is somewhat softer than in the Kazakh steppe. Thus, the climate of Western Siberia cannot be called ideal, but it cannot be called nightmarish either.
Climatic and weather conditions of Eastern Siberia
Eastern Siberia within the Siberian Federal District is Irkutsk region, Republics of Tuva and Buryatia, Zabaykalsky Krai, as well as the southern part of the Krasnoyarsk Territory. The climate of Eastern Siberia can be characterized as sharply continental. The average annual temperature is 0°C. In winter, the temperature can reach up to -40°C, but due to the absence of winds, the cold is relatively easy to bear. AT winter time year, in the north of Eastern Siberia, polar nights can be observed. Total darkness reigns, the sun may not appear for a month, or even more. The climate of Eastern Siberia is a very sunny summer, during which it rarely rains. Maximum temperature in July-August it does not reach more than +15°С. Snow begins to fall in October, with a height of about 20-25 centimeters. During the year, precipitation falls in an amount of 300 to 500 mm per year, and in mountainous areas about 900-1000 mm.
The climate of the northern regions of Siberia.
The northern territories of the Krasnoyarsk Territory, including the Dolgano-Nenetsky and Evenki regions, are almost a real tundra. Here, the climatic conditions are so severe that they could easily become the prototype of the prototype that has developed about the Siberian climate. There is practically no summer in these parts, and the winter period is not only quite long, but also frosty. The duration of the time period with air temperature >10 °C in practice is less than one calendar month. In winter, the thermometer can easily drop below -40°C, and in summer it rarely rises above +10°C. In the mountainous and northern regions, snow cover lies all year round. Perhaps this is the real Siberia, the climate of which is a real test of the will and endurance of a person.
Weather conditions in different regions of Siberia.
In addition to a general description of the climatic conditions of Siberia, we have prepared descriptions of climate and weather for each of the 12 regions of the Siberian Federal District. More information about the weather in a particular city of the Siberian Federal District can be found here:
The temperate climate in the territory of Western Siberia is characterized by greater continentality compared to the ETR. The inflow increases, the annual air amplitude increases, in the southern regions the climate becomes arid. To the east of the ridge, the influence is completely weakened and continental ones prevail here. The climate of Western Siberia is more homogeneous than on the other side of the Urals on European territory.
During the cold period, cyclonic activity resumes in the north and cold continental air enters from Central Siberia, which makes temperature regime unstable. In January, in most of Western Siberia, day-to-day temperature fluctuations average 5°. (Such a phenomenon is almost never observed in other regions of the globe.) The winter is cold, the average temperature in January varies from -18° in the south to -28, -30° in the northeast. With little winter precipitation in the southern regions, the height is less than 30 cm. In the northeast, in the region of the Upper Taz and Lower Yenisei Uplands, where it is frequent, it increases to 80 cm.
In summer, cyclones develop over the entire territory of Western Siberia. Their number decreases from north to south. The northern regions are invaded by cyclones from the European part of Russia and the Atlantic. Cyclones come to the southern regions from the west and southwest (from the lower reaches, from the seas). The most intense cyclonic activity is observed between 54 and 60°N. sh. During the summer period, from 300 to 400 mm of precipitation falls here. To the north and south of this territory decreases. In summer, arctic air comes in, which turns into continental. The influx of air increases dryness and increases continentality towards the south.
Most of Western Siberia has a humid climate. The zero isoline of the difference in precipitation and evaporation, which is the southern boundary of the forest, runs approximately along the line - Novosibirsk (56 ° N). the region of Western Siberia is the most waterlogged territory of Russia. There is a significant accumulation here. surface water, forests are swamped. Precipitation, the annual amount of which is 600 mm, in most of the territory exceeds evaporation by 100 - 200 mm. A lot of solar heat is spent on evaporation. Averages vary from north to south from 14 to 18°. South of 56°N sh. cyclonic activity weakens and the annual amount of precipitation decreases to 350 - 400 mm. Possible evaporation exceeds the amount of precipitation, the climate becomes arid. Dominate.